In the absorbent product technology, many attempts have been made to optimise the absorbent capacity and efficiency of absorbent cores by providing regions of increased or diminished basis weight and density in such cores. Also, it has been attempted to reduce leakage by providing barrier structures to the absorbent products to reduce liquid migration towards and beyond the perimeter of the absorbent product.
From EP-A-052 413 it is known that for absorbent products, leakage of liquids along the waist edge can be prevented by providing a barrier sheet located between the topsheet and the backsheet and the waist ends of an absorbent article. The barrier sheet overlies the core at a waist end and prevent liquids from being squeezed out of the transverse edges of the core.
From EP-A-376 022 (Robertson) a unitary waistcap-waist band is known, wherein a unitary piece of elastomeric material extends from the perimeter of the absorbent product towards the core. The single piece of elastomeric material provides a waist elastic as well as a stand-up barrier overlying the topsheet at the waist end of the core.
From U.S. Pat. No. 4,695,278 (Lawson) an absorbent article is known comprising an elasticated stand-up barrier cuff in the leg areas.
From U.S. Pat. No. 4,795,454 (Dragoo) an absorbent article is known comprising an elasticated stand-up barrier cuff that is connected with a proximal edge to the absorbent article, and is located adjacent a gasketing cuff. A liquid-pervious topsheet terminates inboard of the proximal edge of the barrier cuff. Seal means are located along the proximal edge to prevent wicking of liquids underneath the barrier cuff.
From EP-B-0 304 631 it is known to coat and seal lateral portions of a liquid-permeable topsheet with a hot-melt adhesive to prevent lateral leakage of liquids.
In U.S. Pat. No. 4,935,022 (Lash) an absorbent structure is disclosed which has a lower storage layer and an upper acquisition/distribution layer comprising chemically stiffened cellulose fibers and absorbent gelling material. The upper acquisition/distribution layer is of larger surface area than the underlying storage layer. The lower storage layer is formed of an insert, which is placed relative to the upper acquisition/distribution layer such that about 75% of the absorbent gelling material in the lower layer is found in the front two-thirds section of the absorbent structure, and at least 55% of the total amount of absorbent gelling material is found in the front half section.
In U.S. Pat. No. 4,685,915 (Hasse) an absorbent product is disclosed having a core comprising hydrophilic fibers and absorbent gelling material, the core having an area of higher average density and basis weight than the end portions of the core. The area of higher average density and basis weight is located near the center or the front of the absorbent product.
In U.S. Pat. No. 4,834,735 (Alemany) an absorbent core is disclosed having a storage zone and an acquisition region of lower average density and basis weight than the storage zone. The core comprises a mixture of hydrophilic fibers and absorbent gelling particles. The acquisition region is located towards the front of the absorbent core.
In European patent no EP-B-0 330 675, it is disclosed to introduce absorbent gelling material into specific locations of a horizontal, or x-y plane of an absorbent core using pulsed powder spray guns.
In International patent application no's WO 91/11163 and WO 91/11165, a dual layer core is disclosed comprising a lower storage layer and an upper fluid acquisition/distribution layer comprising chemically stiffened cellulose fibers, the upper layer being substantially free of absorbent gelling material. The area of the acquisition/distribution layer is between 25% and 100% of the area of the lower storage layer, and is preferably of elongated shape. For adult incontinence products, the acquisition/distribution layer is generally located in the front two thirds of the absorbent article, relative to the backsheet.
In U.S. Pat. No. 4,411,660 (Dawn), an absorbent article is disclosed in which a layer consisting of absorbent gelling material underlies a fibrous layer. The layer of absorbent gelling material can be in the form of particles, fibers or a film.
In International patent application WO 91/04724, a diaper core is disclosed which linearly tapers from a relatively narrow crotch section to a relatively wide back section.
EP-A-0 532 035 discloses an absorbent article especially adapted for newborn babies, having cushion barriers to prevent leakage and reduce redmarking of the very sensitive skin.
It has been found by the applicant that in absorbent products which are intended for use by walking infants or adults in a primarily lying-down position, the combination of a wet structure and a relatively high pressure on certain parts of the anatomy, contributes to development of skin complaints. The majority of adults suffering from a severe incontinence are elderly women, for which leakage in this position is relatively frequent compared to other users.
It is an object of the present invention to provide an absorbent product which provides reduced leakage when used in a lying down position.
It is another object of the invention to provide an absorbent article that is especially adapted for users ranging from walking infants to adults, when confined to a predominantly lying down position.
It is a further object of the invention to provide such an absorbent article which especially reduces leakage among woman users when confined to a predominantly lying down position.
It is still another object of the invention to provide an absorbent structure especially adapted for users ranging from walking infants to adults, which product maintains improved dryness in the lying-down position of the user and in which the negative effects of pressure build-up on specific parts of the anatomy are reduced.